#include <iostream>
using namespace std;
#include <iomanip>
using std::setw;
#include <cmath>
#include <cstdlib>

void ex_change(int &a,int &b);

int main()
{
	int a=1,b=2;
	ex_change(a,b);
	cout << a << " " << b;
	return 0;
}

void ex_change(int &a,int &b)
{
	int c = a;
	a = b;
	b = c;	
}
